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Results for “depth adaptation”

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PubMed1977

[Use of mathematical analysis of the cardiac rhythm in evaluation of the functional state of a patient in surgical interventions].

In 112 patients mathematical analysis of the cardiac rhythm indices and a biochemical investigation were effected during operative interventions with diverse types of endotracheal anesthesia. The correlation analysis of the cardiac rhythm parameters showed that at the most traumatic moment of the operation the synchronization of the functional links aimed at maintaining homeostasis was going up. Pharmacological block of adrenergic receptors results in weakening correlational interlinks. By analyzing the degree of synchronization marking functional links of the cardiac rhythm parameters that characterize the vegetative homeostasis it becomes possible to obtain information as to the level of the level of the adaptive-regulatory mechanisms tension and the correspondence of the depth of anesthesia to the seriousness of the operation trauma at different stages of surgery.

Acid-Base Equilibrium↗

PubMed1987

[The criteria of radiotherapy for treating carcinoma of the esophagus].

The criteria of radiation therapy is given for the treatment of a carcinoma of the esophagus, said criteria decided by a committee of the Japanese Association for Radiotherapy Systems at the request of the Japan Radiological Society. The indication for radiation therapy is described and adapted to the new TNM Classification, based on the depth of the invasion of the tumor. The depth of the tumor invasion is divided into 4 stages and the radiological images for each are shown. To evaluate the effect of radiotherapy, cases are divided into curable and non-curable groups, according to the degree of changes of the radiological findings after irradiation, and each group is further subdivided into absolute and relative categories.

Esophageal Neoplasms↗

PubMed1981

Transplantation, identity and drug addiction.

This report is the follow-up of an earlier work in which the authors set forth some considerations on the psychopathological aspects connected with the transplantation of young Portuguese from the ex-colonies. The group studied was composed of 22 cases of drug addiction admitted to the Centre for Drug Research and Prophylaxis, Coimbra, over a specified period. A qualitative and quantitative change in drug consumption and an increase in delinquent behaviour were considered of particular interest and specifically linked to transplantation. An initial analysis indicated the enormous importance of the conflict of identity which existed in the transplantation situation which was subsequently explored in more depth. Transplantation put to the test the capacity to adapt and involved profound changes in defensive mechanisms, which under unfavourable social conditions took on a distinctly regressive character. In view of the age group of the cases under study (adolescents), the frustrations resulting from transplantation were thus added to a crisis of maturation which was already regressive in itself. Some clinical examples are provided.

Adolescent↗

PubMed1994

[Laparoscopic cholecystectomy].

The author presents a new surgical procedure-laparoscopic cholecystectomy. Comparing the time interval from introduction to widespread adaption of other new operations this century, such as vagotomy and open cardiac procedures, it took remarkably little time for the surgical community to accept laparoscopic cholecystectomy. To perform endoscopic surgery, surgeons had to improve eye-hand coordination, adapt to a new tactile sensation and lack of depth perception. The laparoscopic cholecystectomy is "here to stay". The author reports preintervention program as well as the procedure and its technique with necessary instruments. Laparoscopic cholecystectomy is a recently developed alternative to open cholecystectomy that is rapidly gaining popularity because patients have experienced reduced stay in hospital, decreased wound pain and early return to normal activity.

Cholecystectomy, Laparoscopic↗

PubMed2001

Temporal contrast adaptation in the input and output signals of salamander retinal ganglion cells.

We investigated how the light-evoked input and output signals of salamander retinal ganglion cells adapt to changes in temporal contrast, i.e., changes in the depth of the temporal fluctuations in the light intensity about the mean. Increasing the temporal contrast sped the kinetics and reduced the sensitivity of both the light-evoked input currents measured at the ganglion cell soma and the output spike trains of the cell. The decline in sensitivity of the input currents after an increase in contrast had two distinct kinetic components with fast (<2 sec) and slow (>10 sec) time constants. The recovery of sensitivity after a decrease in contrast was dominated by a single component with an intermediate (4-18 sec) time constant. Contrast adaptation differed for on and off cells, with both the kinetics and amplitude of the light-evoked currents of off cells adapting more strongly than those of on cells. Contrast adaptation in the input currents of a ganglion cell, however, was unable to account for the extent of adaptation in the output spike trains of the cell, indicating that mechanisms intrinsic to the ganglion cell contributed. Indeed, when fluctuating currents were injected into a ganglion cell, the sensitivity of spike generation decreased with increased current variance. Pharmacological experiments indicated that adaptation of spike generation to the current variance was attributable to properties of tetrodotoxin-sensitive Na(+) channels.

Action Potentials↗

PubMed2000

Salivary epidermal growth factor and intestinal adaptation in male and female mice.

Salivary epidermal growth factor (sEGF) levels are increased in male mice after small bowel resection (SBR) and may be important during intestinal adaptation. Since males have greater sEGF than females, the influence of sex on postresection adaptation was tested. Females had lower sEGF; however, sEGF substantially increased in both sexes after a massive (50%) SBR. Adaptive increases in DNA and protein content, villus height, and crypt depth, as well as crypt cell proliferation rates in the remnant ileum, were not different between males and females. Although significant postresection increases in sEGF were identified, EGF mRNA and protein did not change within the submandibular gland. Glandular kallikrein-13 and ileal EGF receptor expression were greater after SBR in female mice. Intestinal adaptation is equivalent in female and male mice after SBR. Despite lower sEGF, females demonstrated increased expression of a kallikrein responsible for sEGF precursor cleavage as well as amplified ileal EGF receptor expression. These results endorse an important differential response between sexes regarding sEGF mobilization and intestinal receptor availability during adaptation.

Adaptation, Physiological↗

PubMed2003

Ileal resection enhances jejunal absorptive adaptation for water and electrolytes to extrinsic denervation: implications for segmental small bowel transplantation.

BACKGROUND/PURPOSE: Segmental small bowel transplantation (SBT) may be an alternative to whole jejunoileal SBT. The aim of this study was to evaluate adaptability of extrinsically denervated jejunum after ileectomy. METHODS: Baseline absorption of an isomolar, nonnutrient electrolyte solution was measured in an 80-cm in situ jejunal segment. Control (CON) and extrinsically denervated dogs (EXT DEN) then underwent distal 50% enterectomy; EXT DEN dogs also underwent a complete extrinsic denervation of remnant jejunum. Absorption was remeasured 2 and 12 weeks later; jejunal biopsies at 12 weeks were compared with baseline. RESULTS: All dogs experienced weight loss and diarrhea, which resolved by 10 weeks in CON but persisted in EXT DEN dogs. Net absorptive fluxes of water, Na+, K+, and Cl-, however, remained unchanged in both groups 2 weeks and 12 weeks after denervation. Morphometric evaluation showed an increase in crypt depth in both groups at the 12-week time-point. CONCLUSIONS: Despite a clinical short bowel syndrome, more weight loss, and diarrhea in EXT DEN, there were no temporal differences in net absorptive fluxes of water and electrolytes within or between these 2 groups, and both developed increased crypt depth at 12 weeks. Extrinsic denervation does not blunt jejunal adaptive response to ileectomy.

Adaptation, Physiological↗

PubMed2004

[Vitamin A effects on morphometric adaptation after extensive small bowel resection in the rat].

This work was conceived to study, in the rat short bowel syndrome, the effect of precocious administration of retinoic acid on morphometric adaptation in the remnant intestine. Mitotic index, villous height, crypt depth and mucosal aspect were determined in 2 groups of rats (n=12) after 60% small bowel resection. 100 microg of retinoic acid were perfused immediately after resection in the first group. Control group rats received placebo. Two similar groups (n=12) underwent intestinal transection with or without retinoic acid perfusion. Our results show that retinoic acid induced precocious and significant enhancement of all morphometric parameters when compared to placebo.

Adaptation, Physiological↗

PubMed1990

The role of alterations in membrane lipid composition in enabling physiological adaptation of organisms to their physical environment.

It is clear from the literature reviewed that modifications in membrane lipid composition play a major role in the adaptation of diverse organisms to specific environments and physiological circumstances. Acyl chain and molecular species restructuring in phospholipids are the most ubiquitous adaptations to environmental insult, being implicated in membrane adjustments to temperature, pressure, water activity, pH and salinity. In contrast, other adaptations (e.g. modulation of anionic phospholipids (salinity adaptation), trehalose content (dehydration) and the PC/PE ratio (temperature acclimation] appear to be more context specific. Although the volume of correlative data relating membrane composition to environmental state is impressive, several questions must be explicitly addressed in future research if a mechanistic understanding of the role of lipids in fine tuning membrane function is to be achieved. These include: (1) Adaptation thresholds--How much environmental variation is required before an acclimatory response is initiated, and is the extent of membrane perturbation induced by such minimally effective stimuli similar for different stress vectors? Interspecific comparisons of the Na+/K(+)-ATPase of fish collected at different depths indicate that species must be separated in depth by a distance corresponding to a pressure difference of 20 MPa before pressure adaptation is evident. Assuming a dT/dP value of 0.23 (Table 1), a 20 MPa change in pressure corresponds to ca. a 5 degrees C change in temperature, which agrees well with the minimal temperature change required to elicit changes in the lipid composition of plasma membranes in kidney tissue of thermally-acclimating trout. A pressure of 20 MPa also corresponds approximately to the maximum depth from which deep sea animals survive being brought to the surface. Collectively, these observations suggest that the minimally effective stimuli for both temperature and pressure adaptation are similar. Comparable data are not available for other environmental variables. (2) Signal transduction--What signals are being sensed and how are they transduced into an adaptational response? In some cases, it is clear that the enzymes of lipid metabolism respond directly (either by a variation in catalytic rate or substrate preference) to variations in the physical environment in an apparently adaptive manner (e.g. refer Sections VI.A.1 and VI.B.2). It seems unlikely, however, that such direct effects can explain the totality of the adaptive capacity of organisms, especially given the evidence for the induction of desaturase synthesis in cold adaptation (refer to Section VI.A.2).(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗

PubMed2004

Design of biological filter for iron and manganese removal from water.

The technology core of biological removal of iron and manganese by contact oxidation is iron and manganese oxidizing bacteria. This article made a study on down flow and up flow filtration, the results show that down flow filtration of the homogenous filter medium is more adapted to the reproduction of biotic formation. Homogeneous filter increase the depth of effective biological filter and the biomass that develop the bio-chemical capability of the biological filter. Homogeneous filter increase removal capability of Fe/Mn and alleviate the formation of sludge cake, which can get a quite backwash. Down flow homogeneous biological filter can solve some engineering problems of heterogeneous up flow filtration. The down flow homogeneous biological filter is more adapted to the removal of Fe/Mn in groundwater.

Bacteria↗

PubMed1999

The adaptive intestinal response to massive enterectomy is preserved in c-SRC-deficient mice.

BACKGROUND/PURPOSE: The Src family of protein tyrosine kinases has been implicated in the downstream mitogenic signaling of several ligands including epidermal growth factor (EGF). Because EGF likely plays a role in adaptation after massive small bowel resection (SBR), we tested the hypothesis that c-src is required for this important response. METHODS: A 50% proximal SBR or sham operation (bowel transection or reanastomosis alone) was performed on c-src-deficient (n = 14) or wild-type (C57bl/6) mice (n = 20). The ileum was harvested on postoperative day 3 and adaptive parameters determined as changes in ileal wet weight, protein and DNA content, proliferation index, villus height, and crypt depth. Comparisons were done using analysis of variance (ANOVA), and a Pvalue less than .05 was considered significant. Values are presented as mean +/- SEM. RESULTS: The activity of c-src was increased in the ileum of wild-type mice after SBR but remained unchanged in c-src-deficient mice. Despite this lack of increase, adaptation occurred after SBR in the c-src-deficient mice as demonstrated by increased ileal wet weight, protein and DNA content, proliferation index, villus height, and crypt depth similar to wild-type mice. CONCLUSIONS: The adaptive response of the intestine to massive SBR is preserved despite reduced activity of the c-src protein. The mitogenic signaling that characterizes intestinal adaptation and is associated with receptor activation by EGF or other growth factors probably occurs by mechanisms independent of c-src protein tyrosine kinase.

Adaptation, Physiological↗

PubMed2001

On the extended depth of focus algorithms for bright field microscopy.

Microscopes offer a limited depth of focus which precludes the observation of a complete image of a three-dimensional (3D) object in a single view. Investigations, by a variety of researchers, have led to the development of extended depth of focus algorithms for serial optical slices of microscopic 3D objects in recent years. However, to date, no quantitative comparison of the different algorithms has been performed, generally leaving the evaluation to the subjective qualitative appreciation of the observer. In this paper we use three different tests for extended depth of focus algorithm evaluation and test 10 different algorithms, some of them have been adapted (by us) for a series of optical slices. However, the main contribution of the paper is a new improved algorithm for computing the extended depth of focus.

Algorithms↗

PubMed2006

Fully adaptive FEM based fluorescence optical tomography from time-dependent measurements with area illumination and detection.

Using an area-illumination and area-detection scheme, we acquire fluorescence frequency domain measurements from a tissue phantom with an embedded fluorescent target and obtain tomographic reconstructions of the interior fluorescence absorption map with an adaptive finite element based scheme. The tissue phantom consisted of a clear acrylic cubic box (512 ml) filled with 1% Liposyn solution, while the fluorescent targets were 5 mm diameter glass bulbs filled with 1 microM Indocyanine Green dye solution in 1% Liposyn. Frequency domain area illumination and detection employed a planar excitation source using an expanded intensity modulated (100 MHz) 785 nm diode laser light and a gain modulated image intensified charge coupled device camera, respectively. The excitation pattern was characterized by isolating the singly scattered component with cross polarizers and was input into a dual adaptive finite element-based scheme for three dimensional reconstructions of fluorescent targets embedded beneath the phantom surface. Adaptive mesh refinement techniques allowed efficient simulation of the incident excitation light and the reconstruction of fluorescent targets buried at the depths of 1 and 2 cm. The results demonstrate the first clinically relevant noncontact fluorescence tomography with adaptive finite element methods.

Algorithms↗

PubMed1996

Information, support, and communication needs of women with a family history of breast cancer.

In this article, the role of information, support, and communication in promoting adaptation to the risk of breast cancer is reported. These variables emerged from an in-depth study of women at risk for breast cancer because of breast cancer in one or more of their primary (first degree) relatives. Fifty-five women with mothers, sisters, mother and sister, or mother and another primary relative were interviewed using in-depth semi-structured, tape-recorded interviews. After transcription, data were analyzed using qualitative analysis procedures. A three-phase process of adaptation to the risk of breast cancer was uncovered, which was subsequently validated with two study participants. Information, support, and communication emerged as important factors in facilitating the adjustment of women throughout the three phases of the process: as women "lived" the breast cancer experience of their relative; as they developed a perception of their personal risk for breast cancer; and finally as they put the risk of breast cancer "in its place." Despite the importance of information and support, most women had difficulty meeting these needs. Also, communication patterns both within the family and with health professionals were generally not helpful for these women. Issues related to the ill relative as "manager" of cancer-related information, the "ownership style" of the woman at risk, and the accessibility and availability of resources influenced women's adaptation to feelings of risk. Women's needs for information, support, and communication and facilitating factors are described in detail, and recommendations for clinical practice and research offered.

Adult↗

PubMed2005

Targeted intestinal overexpression of the immediate early gene tis7 in transgenic mice increases triglyceride absorption and adiposity.

Following loss of functional small bowel surface area due to surgical resection, the remnant gut undergoes an adaptive response characterized by increased crypt cell proliferation and enhanced villus height and crypt depth, resulting in augmented intestinal nutrient absorptive capacity. Previous studies showed that expression of the immediate early gene tis7 is markedly up-regulated in intestinal enterocytes during the adaptive response. To study its role in the enterocyte, transgenic mice were generated that specifically overexpress TIS7 in the gut. Nucleotides -596 to +21 of the rat liver fatty acid-binding protein promoter were used to direct abundant overexpression of TIS7 into small intestinal upper crypt and villus enterocytes. TIS7 transgenic mice had increased total body adiposity and decreased lean muscle mass compared with normal littermates. Oxygen consumption levels, body weight, surface area, and small bowel weight were decreased. On a high fat diet, transgenic mice exhibited a more rapid and proportionately greater gain in body weight with persistently elevated total body adiposity and increased hepatic fat accumulation. Bolus fat feeding resulted in a greater increase in serum triglyceride levels and an accelerated appearance of enterocytic, lamina propria, and hepatic fat. Changes in fat homeostasis were linked to increased expression of genes involved in enterocytic triglyceride metabolism and changes in growth with decreased insulin-like growth factor-1 expression. Thus, TIS7 overexpression in the intestine altered growth, metabolic rate, adiposity, and intestinal triglyceride absorption. These results suggest that TIS7 is a unique mediator of nutrient absorptive and metabolic adaptation following gut resection.

Adipose Tissue↗

PubMed2005

Effect of sex and sex hormones on structural intestinal adaptation after massive small bowel resection in rats.

PURPOSE: The gonadal steroids play a major role in the regulation of many functions. The purpose of the current study was to evaluate the effect of sex and sex hormones on intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: In the first experiment, male and female Sprague-Dawley rats underwent bowel transection and re-anastomosis (sham group) or 75% small bowel resection and anastomosis (SBS group). Relative changes in parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) were measured on day 15 and were compared with respect to sex. In the second experiment, male rats were divided into 4 experimental groups: SBS rats, SBS castrated rats, SBS castrated rats treated with testosterone, and SBS castrated rats treated with estradiol. Parameters of intestinal adaptation were compared with respect to hormonal treatment. Statistical significance was determined by Student's t test and analysis of variance with P < .05 considered significant. RESULTS: Sex had minimal effects on intestinal adaptation. Both male and female rats showed a comparable increase in all parameters of intestinal adaptation. In the second experiment, castration led to significant decrease in bowel and mucosal weight, mucosal DNA and protein in both jejunum and ileum compared with SBS animals. Castrated rats also had lower jejunal villus height and crypt depth compared with SBS animals. Testosterone attenuated this negative effect of castration on bowel regrowth. Rats treated with testosterone showed a significant increase in bowel and mucosal weight, mucosal protein in both jejunum and ileum, mucosal DNA, villus height, and crypt depth in jejunum compared with castrated nontreated animals. Treatment with estradiol after resection and castration had minimal effect on bowel regrowth. CONCLUSIONS: Bowel regrowth after massive small bowel resection is not sex-related. Depletion of androgens by castration inhibited intestinal adaptation. Testosterone has shown a strong stimulating effect on bowel regrowth.

Adaptation, Physiological↗

PubMed1997

The development and evaluation of an adaptable computer aided instruction(CAI) program for acquiring problem solving skills in biochemistry on the WWW: The "BioChem Thinker".

BioChem Thinker is a CAI program that was developed to enhance problem solving skills and ability to integrate knowledge in biochemistry for medical and dental students. The program runs on a WWW browser. BioChem Thinker is adaptable, it enables the teacher to create a new problem solving assignment, or edit existing assignments without in-depth knowledge of computer programming. This provides teachers with greater independence and flexibility so as to be able to adapt the program to their own course requirements. The program was implemented and evaluated in the 3rd year biochemistry course of The Hebrew University-Hadassah Medical School. The tool used to develop Biochem Thinker can be utilized to develop similar CAI in other biomedical areas.

Biochemistry↗

PubMed2002

Acquired monocular vision: functional consequences from the patient's perspective.

PURPOSE: The study is conducted to determine the effect of acquired monocular vision (enucleation, phthisis) on the daily activities of patients. METHODS: Sixty-five patients in a case series completed a 30-question survey evaluating the functional consequences of monocular vision. RESULTS: Patients with sudden visual loss adapted more slowly than those with gradual loss (8.8 versus 3.6 months). Difficulties with depth perception and cosmesis were prevalent. Unexpected consequences included neck pain, strain with reading, employment change, depression, car accidents, and alcoholism. Ninety-one percent of patients had no formal training to help them adapt. CONCLUSIONS: More than previously appreciated, there are many obstacles that patients face in making the transition to monocular vision. Few patients receive any formal instruction to help them adapt, yet many indicate that it would be beneficial.

Activities of Daily Living↗